A new murine model for bronchiolitis obliterans post-bone marrow transplant

Area of Science:

• * Immunology and Transplantation Science
• * Pulmonary Medicine and Pathology

Background:

• * Bronchiolitis obliterans (BO) is a significant complication following lung transplantation and hematopoietic stem cell transplant (HSCT).
• * Current mouse models do not adequately represent the late-onset pulmonary complications seen in patients, hindering therapeutic development.

Purpose of the Study:

• * To develop a novel mouse model that accurately replicates bronchiolitis obliterans (BO).
• * To facilitate the study of BO's onset and progression, particularly in the context of late complications after HSCT.

Main Methods:

• * Establishment of a mouse model using lethally conditioned recipients receiving T-cell-depleted allogeneic bone marrow (BM) with a sublethal dose of allogeneic T cells.
• * Assessment of lung pathology, inflammation markers, airway function, and graft-versus-host disease (GVHD) at two months post-transplant.

Main Results:

• * The developed model exhibited extensive perivascular and peribronchiolar inflammation in the lungs, including T cells, B cells, macrophages, neutrophils, and fibroblasts.
• * Histological analysis confirmed airway obstruction consistent with BO, along with epithelial cell changes and evidence of pulmonary edema and fibrosis.
• * Mice displayed impaired lung function (high airway resistance, low compliance) and early increases in inflammatory mediators.

Conclusions:

• * The established mouse model effectively mimics late-onset BO following allogeneic HSCT.
• * This model is valuable for investigating BO associated with chronic GVHD and improving outcomes in lung transplant recipients.